Larska Magdalena, Krzysiak Michał K, Kęsik-Maliszewska Julia, Rola Jerzy
Department of Virology, National Veterinary Research Institute, Al. Partyzantów 57, 24-100, Puławy, Poland.
European Bison Breeding Center, Bialowieża National Park, Park Pałacowy 11, 17-230, Białowieża, Poland.
BMC Vet Res. 2014 Dec 21;10:967. doi: 10.1186/s12917-014-0307-3.
In view of recurrent Schmallenberg virus (SBV) infections all over Europe between 2011 and 2013, a lively scientific debate over the importance of the sylvatic transmission cycle of the virus has emerged. The study presents results of serosurvey which included wild ruminants representing species of red deer (Cervus elaphus), roe deer (Capreolus capreolus), European bison (Bison bonasus), fallow deer (Dama dama), mouflon (Ovis orientalis musimon) hunted or immobilized at 34 different locations of Poland in the autumn/winter 2013.
Out of 580 sera, 145 (25%) were considered positive for SBV antibodies. The overall SBV seroprevalence calculated using district probability weights was estimated at 27.7% (95% CI: 24.0-31.4). The seroprevalences at the district level varied between 0 and 80.0% (95% CI: 24.5-135.0%) with the mean within-district prevalence of 24.0% (95% CI: 16.5-31.4). Significantly higher seroprevalence was observed in animals from the Eastern provinces (36.6%) compared to the Western provinces (22.8%). SBV infection impact varied significantly between different species (higher SBV seroprevalence in larger species such as European bison), population type (free-ranging; captive), age, body weight, percent of the district forest area, part of Poland, and the densities of wild and domestic ruminants at the district and province level. Using statistical multivariable logistic model, population type, age, part of Poland and domestic ruminant density were identified as the main risk factors for SBV infection in wild ruminants in Poland.
SBV seroprevalence in wild ruminants, similarly to the epizootic situation in domestic ruminants in the country, varied significantly between districts and provinces. Association between SBV seropositivity, species, animal body weight and age group expressed by a higher prevalence in larger ruminants may be explained by more frequent exposure to midge-vector bites of the latter, however it might also be related to the different species susceptibility to SBV infection. The positive effect of higher domestic ruminant density on the risk of SBV infection in wildlife and lower SBV seroprevalences in the latter suggested that the sylvatic cycle of SBV transmission is an effect of the pathogen spillover from the domestic animals.
鉴于2011年至2013年间欧洲各地反复出现施马伦贝格病毒（SBV）感染情况，关于该病毒野生传播循环重要性的科学辩论愈演愈烈。本研究呈现了血清学调查结果，该调查涵盖了2013年秋冬在波兰34个不同地点猎捕或固定的野生反刍动物，包括马鹿（Cervus elaphus）、狍（Capreolus capreolus）、欧洲野牛（Bison bonasus）、黇鹿（Dama dama）、摩弗伦羊（Ovis orientalis musimon）。
在580份血清样本中，145份（25%）被判定为SBV抗体阳性。使用地区概率权重计算得出的总体SBV血清阳性率估计为27.7%（95%置信区间：24.0 - 31.4）。地区层面的血清阳性率在0至80.0%之间变化（95%置信区间：24.5 - 135.0%），地区内平均患病率为24.0%（95%置信区间：16.5 - 31.4）。与西部省份（22.8%）相比，东部省份动物的血清阳性率显著更高（36.6%）。SBV感染影响在不同物种（如欧洲野牛等较大物种的SBV血清阳性率更高）、种群类型（自由放养；圈养）、年龄、体重、地区森林面积百分比、波兰地区以及地区和省份层面的野生和家养反刍动物密度之间存在显著差异。使用统计多变量逻辑模型，确定种群类型、年龄、波兰地区和家养反刍动物密度是波兰野生反刍动物感染SBV的主要风险因素。
野生反刍动物中的SBV血清阳性率，与该国家养反刍动物的流行情况类似，在不同地区和省份之间存在显著差异。SBV血清阳性与物种、动物体重和年龄组之间的关联表现为较大反刍动物患病率更高，这可能是因为后者更频繁地接触蠓媒叮咬，但也可能与不同物种对SBV感染的易感性有关。较高的家养反刍动物密度对野生动物感染SBV风险的积极影响以及野生动物中较低的SBV血清阳性率表明，SBV传播的野生循环是病原体从家畜溢出的结果。
